1. Field of the Invention
This invention relates to an immunoglobulin preparation, more specifically, an immunoglobulin preparation having excellent storage stability.
2. Description of the Related Art
Among .gamma.-globulins which are plasma protein components, an immunoglobulin preparation comprising IgG has been used for preventing and treating various infectious diseases. The immunoglobulin is unstable in the form of a solution. It is known that as a result of the aggregation of immunoglobulin, in other words, as a result of the denaturation of the immunoglobulin during the fractionating operation resulting in the formation of a polymer or dimer of immunoglobulin, the immunoglobulin shows a marked increase in the complement-fixing property which is called anticomplementary action, leading to a) lowering the serum complement concentration upon intravenous administration to a human body or b) serious side effects such as anaphylactic shock. Accordingly, immunoglobulin has been formulated not as a liquid preparation but as a dry preparation, particularly, in a lyophilized form. However, the dry preparation is accompanied with the problem that it cannot be administered easily because of the necessity of dissolving it in distilled water for injection or the like upon use.
On the other hand, the liquid preparation does not require any dissolving operation in distilled water for injection or the like and can be administered easily compared with the dry preparation. As described above, however, it is accompanied with such drawbacks as inferiority in the stability of immunoglobulin. Accordingly, there has conventionally been an attempt to develop a liquid composition of immunoglobulin for intravenous injection having stability even in the form of a solution.
For example, JP-A-63-192724 (the term "JP-A" as used herein means an "unexamined published Japanese patent application" (U.S. Pat. No. 4,876,088, EP 278422)) discloses a liquid globulin composition for intravenous injection having stability even in the form of a solution, said composition having a low conductivity and pH of 5.5.+-.0.2 and containing sorbitol as a stabilizer. In addition, JP-A-58-43914 (U.S. Pat. Nos. 4,396,608 and 4,499,073, EP 73371) discloses that in order to obtain an immunoglobulin composition which is substantially free of an aggregate of immunoglobulin and has a monomer content of immune serum globulin exceeding about 90%, a solution of the immune serum globulin is adjusted to have an ionic strength less than about 0.001 and a pH of 3.5 to 5.0.
JP-A-63-8340 (U.S. Pat. Nos. 4,762,714 and 4,948,877, EP 240856) discloses a process for preparing immune serum globulin substantially free of an acquired virus, which comprises obtaining immune serum globulin from the human plasma source by the cold ethanol fractionating method at a pH of about 5.4 or lower and storing the immune serum globulin at a pH of about 4.25 or lower for at least about three days or storing it at a pH of about 6.8 or lower and a temperature of at least 45.degree. C. so as not to contain an infectious retrovirus substantially. However, the above-described invention aims at the inactivation of a retrovirus. It has not been reported that the immunoglobulin preparation thus obtained shows an improvement in the aggregation-wise problem of immunoglobulin.
JP-A-7-238036 (EP 702960) discloses that for the improvement of stability, the aggregation of immunoglobulin, in other words, an increase of not only a polymer of immunoglobulin but also a dimer of immunoglobulin is suppressed by acid treatment or storage at room temperature.
WO 95-3826 discloses the immunoglobulin preparation comprising 0.1 g/L or less of non-ionic surfactant as stabilizer for maintaining solution state, and being substantially free of albumin.